Time Ephemerides Credits

The JPL ephemerides

The JPL ephemerides represent mankind's best knowledge of the positions and velocities of all major bodies of the solar system over centuries (short ephemerides) and millennia (long ephemerides). These data are determined by solving the equations of motion for the solar system bodies using starting conditions that have been determined by a least squares fit to all the relevant historical and modern astronomical observations of those bodies. I want to thank the members of the JPL team (formerly lead by Myles Standish and currently lead by William Folkner) for continuing to do this exacting research and for publicly distributing the results in a standard form that is straightforward for ephemeris manipulation and interpolation software such as ephcom2 to use.

The ephcom1 source code

The "ephcom1" software was developed by Paul Hardy and released at the ephemeris.com website in 2004 under the LGPL. I want to thank Paul for his development effort which has made ephcom2 (a substantially modified and improved version of ephcom1) possible.

The logo

The Time Ephemerides logo is a modified version of the "Big Ben Clockface" png file which is copyright Darren Burnhill. The original and modified versions are licensed under the Creative Commons Attribution-Share Alike 2.0 UK: England & Wales License.

The modifications (to replace white with gray, resize, and apply the "Time Ephemerides" annotation) were performed as follows using the ImageMagick "convert" application:

	  convert big_ben_clock_face.png -fill 'rgb(100,100,100)' -opaque \
	  'rgb(255,255,255)' -geometry 456x120! big_ben_clock_face_color.png
	  convert big_ben_clock_face_color.png -fill "#FF6600" -stroke black  \
	  -font  FreeSans-Bold -pointsize 36 -gravity center \
	  -annotate 0 "Time Ephemerides" timeephem_logo.png